1. Field of the Invention
The present invention relates generally to health fields involving patient care. Specifically, the present invention relates to sensing and monitoring systems providing for sensing and monitoring of patient movement and further relates to systems providing for the determination of the presence or absence of a patient. Embodiments of the present invention provide systems that may be implemented in a bed, chair, wheelchair, or other configurations. The present invention provides a patient sensing and monitoring system which allows for system control, sensing, and monitoring in a configuration that is self-contained. The invention may be especially applicable for patient sensing and monitoring as a system which provides programmable control and the ability for health care personnel to monitor patients remotely.
2. Description of the Related Art
Monitoring the presence of patients in a bed, chair, wheelchair, or the like, is a significant problem for many care facilities, such as hospitals and nursing homes. Patients are typically expected to remain in their bed to protect them from injuring themselves if they should exit from bed unassisted and become injured due to their weakened physical condition or other physical or mental impairment. It is important, therefore, for care providers to be notified quickly when a patient leaves a bed. This problem is serious in all health care settings, including hospitals, assisted living, and home care and is especially pronounced in nursing homes, where a large percentage of these facilities' patients are in weakened physical conditions. Physical restraints on patients, which were used routinely in the past to address these problems are now rarely practical or acceptable.
Therefore, care facilities have begun to address this growing problem by utilizing a variety of devices that monitor patient movement. For example, U.S. Pat. No. 4,854,323 to Beggs, No. 4,633,237 to Tucknott et al., No. 4,179,692 to Vance, No. 5,144,284 to Hammett, and No. 4,228,426 to Roberts describe a number and variety of sensing devices developed to address some of the needs of the care facilities in monitoring presence or absences of patients on beds.
A conventional bed monitoring device 2 is shown in FIG. 1. Generally, such a monitoring device 2 has a flexible, elongated, pressure-sensitive, switch 6 to sense by closed or opened electric switch contact the presence or absence of a patient P from a bed B. When the patient P is present on the bed B, as illustrated in FIG. 1, the elongated, flexible, switch 6 has closed electric contacts (not shown in FIG. 1). However, if the patient P leaves the bed B or, in some cases, when the patient P merely moves, the electric contacts of switch 6 open. Such closed switch or opened switch conditions create an opened or closed electric circuit on cord 4, which is sensed by a controller an interface box 8 connected to the cord 4. The controller in interface box 8, in response, produces a signal that is in the same format, i.e., mimics, a signal from a conventional nurse call button N. therefore, such a signal from the interface box 8, when connected by another cord 9 to a conventional nurse call circuit C via a conventional nurse call wall connector or socket in the patient's room, activates a light and/or audible alarm of a conventional nurse station monitor M at a remote location to notify the nurse to check on the well-being of the patient P.
In other words, the signal produced by the bed monitoring device 2 is indistinguishable from the signal produced by the conventional nurse call button N, and the nurse call station monitor responds the same to both of them. If the switch portion 6 of the bed monitoring device 2 was connected directly to the nurse call circuit C without the interface box 8, similar to a nurse call button N, it would activate the nurse call monitor M every time the patient P gets out of bed B, even momentarily, and even whenever the patient P moves on the bed B in a manner that removes his or her weight from the switch portion 6. The conventional nurse call monitor M simply responds to a signal on the nurse call circuit C and has no way of distinguishing acceptable patient P activity from patient absence from the bed B that needs attention. Consequently, state-of the-art bed monitors 2 need the controller of interface box 8 to intercept signals from the switch portion 6 and to process such signals in a manner necessary to produce only suitable nurse call signals for the nurse call circuit C. Therefore, the controller in interface box 8 may have logic that produces output signal on cord 9 only after switch portion 6 remains open for some preset time threshold, such as 3-6 seconds, and it may have other features, such as on/off and reset switches, audio and/or visual alarm, timer adjustment, information recorder, and the like.
While the switch portion 6 of the conventional bed monitoring device 2 is flexible, conformable to a soft and deformable bed B surface, and non-obtrusive so as to be comfortable and virtually not noticeable to the tactile senses of the patient P, the conventional interface box 8 is a problem. It is hard, bulky, requires an extra cord 9, and is generally obtrusive and adds to the clutter in typical small and restricted spaces of patient rooms in hospitals and nursing care facilities.
Therefore, some areas in care facilities may lack sufficient space to accommodate the interface box 8 and multiple cords 4, 9 of conventional bed monitor equipment 2, especially if other patient care equipment is necessary, such as equipment monitoring the vital signs of the patient, tray tables, intravenous feeding tubes and stands, nurse call cords and buttons, catheter tubes and bags, leg stimulator drivers and tubes, traction bars and cords, patients' personal effects, and the like. Components of conventional bed monitoring equipment 2, such as the interface box 8, are also inadequately configured to be placed in operationally unobtrusive locations in relation to the working area necessary for nurses, doctors, and other care-giving staff to have accessibility to the patients. For example, placement of components of conventional bed monitoring equipment 2, interface box 8 and cords 4, 9, a patient support surface of a bed B, mattress, or seat of a chair or wheelchair, would detract from the comfort of the patient P, make control of the equipment less accessible, and could compromise the functionality of the system. Further, conventional monitoring systems such as those previously described, which have hardwire or cable connection to external equipment, such as the nurse call circuit C or other monitoring equipment, actually teach away from operationally unobtrusive system features. Consequently, conventional bed monitoring equipment 2 has excessive, obtrusive wire connections and bulky components and tend to restrict busy health care professionals ability to perform their patient care functions and duties.
Consequently, there remain strong and unmet needs for a reliable, simply configured, less complex, and less costly system that can provide care facilities with the necessary control functions and the abilities to remotely monitor the movement, presence, or absence of patients who are confined to beds, chairs, wheelchairs, or other equipment or locations.